David Morales-Morales

Dehydrogenation of secondary amines to imines catalyzed by an iridium PCP pincer complex: initial aliphatic or direct amino dehydrogenation?

Abstract The PCP pincer complex, IrH2(C6H3-2,6-(CH2PBut2)2) catalyzes the transfer dehydrogenation of secondary amines to imines. The catalytic system is highly sensitive to both steric and electronic factors and greater than 99% regioselectivity are observed in the dehydrogenation of the asymmetric substrates, cyclohexyethylamine and benzylpropyl amine. Good to excellent yields are obtained when the reactions are carried out in toluene solution. The dehydrogenation of 2,2,2′,2′-tetramethyldibutylamine leads exclusively to the production of the corresponding imine indicating that the catalytic reaction pathway involves direct amino rather than initial aliphatic dehydrogenation.

Enantioselective synthesis of platinum group metal complexes with the chiral PCP pincer ligand R,R-{C6H4-2,6-(CH2P*PhBut)2}. The crystal structure of R,R-PdCl{C6H3-2,6-(CH2P*PhBut)2}

The novel PCP chiral ligand R , R -{C 6 H 4 -2,6-(CH 2 P *PhBu t ) 2 } and its platinum metal complexes have been easily synthesized in enantiomeric pure form. The palladium compound R , R -PdCl{C 6 H 3 -2,6-(CH 2 P *PhBu t ) 2 } has been characterized by X-ray crystal structure analysis thus confirming the absolute configuration of the complexated ligand. Preliminary catalytic experiments with the iridium and palladium complexes R , R -IrH 4 {C 6 H 3 -2,6-(CH 2 P *PhBu t ) 2 } and R , R -PdCl{C 6 H 3 -2,6-(CH 2 P *PhBu t ) 2 } in the dehydrogenation of cycloalkanes and in the hydrosilylation of styrene, allylic alkylation and Heck coupling reactions, respectively have been carried out.

Highly efficient and regioselective couplings of aryl halides to olefins catalyzed by a palladium complex with a hybrid phosphorus–sulfur ligand

The novel palladium phosphino-thioether P–S chelate complex, [PdCl2{MeSC6H4-2-(CH2PPh2)}] (3) is a highly efficient catalyst for the olefinic coupling of aryl bromo and iodo compounds to olefins under aerobic conditions, leading to more than 10 6 turnovers for the reactions with bromo and iodo benzenes.

Bottom-up design and construction of a non-centrosymmetric network through π–π stacking interactions

Through the careful design of a tecton and the selection of an adequate synthon we were able to design and build a non-centrosymmetric crystal through π–π stacking interactions.

Synthesis of neutral iridium(III) and rhodium(III) complexes with the proligands Pri2P(C6H4SH-2) [priPSH]; PhP(C6H4SH-2)2 [phPS2H2] and PhP(C2H4SH)2 [ePS2H2]. The X-ray crystal structures of [Ir(priPS)3] and [Rh(H)(phPS2)(CO)(PPh3)]

Abstract The reactivity of the hybrid phosphorus–sulfur proligands priPSH, phPS2H2 and ePS2H2 with iridium and rhodium precursors has been explored. By reacting IrCl3 with priPSH in the presence of NEt3 as base, the octahedral Ir(III) specie [Ir(priPS)3] was obtained and its crystal structure determined. Reactions of the potentially tridentated proligands phPS2H2 and ePS2H2 with trans-[MF(CO)(PPh3)2] (M=Rh and Ir) were also investigated. Complexes of general formula [M(H)(phPS2)(CO)(PPh3)] were obtained with phPS2H2. A single crystal X-ray structure determination for [Rh(H)(phPS2)(CO)(PPh3)] showed the complex to be octahedral. Reactions with the aliphatic proligand ePS2H2 afforded analogous species to those with phPS2H2.

High yield olefination of a wide scope of aryl chlorides catalyzed by the phosphinito palladium PCP pincer complex: [PdCl{C6H3(OPPri2)2-2,6}]

[PdCl{C6H3(OPPri2 )2-2,6}] efficiently catalyzes the olefination of a broad scope of aryl chlorides; as a result of the high thermal stability of the catalyst, the coupled products are obtained in excellent and in many cases nearly quantitative yields.

Synthesis of a neutral SPS pincer Pd(II) complex with the proligand PhP(C6H4SH-2)2 [phPS2H2]. The X-ray crystal structure of [Pd(phPS2)(PPh3)]

Abstract The reactivity of the hybrid phosphorus–sulfur proligand phPS2H2 with the trans-[Pd(Cl)2(PPh3)2] precursor has been explored. By reacting trans-[Pd(Cl)2(PPh3)2] with phPS2H2 in the presence of NEt3 as base, the complex [Pd(phPS2)(PPh3)] was obtained. A single crystal X-ray structure determination for [Pd(phPS2)(PPh3)] shown the compound to be square planar with the ligand phPS2 behaving as a SPS pincer ligand.

Diorganotin(IV) complexes with furan-2-carbohydrazone derivatives: synthesis, characterization, crystal structure and antibacterial activity

Four new diorganotin(IV) complexes, R2SnL (L = La: R = Me 1, Ph 2; L = Lb: R = Me 3, and Ph 4), have been synthesized by reaction of hydrazone ONO donors, 5-bromo-2-hydroxybenzaldehyde furan-2-carbohydrazone (H2La) and 2-hydroxynaphthaldehyde furan-2-carbohydrazone (H2Lb) with diorganotin(IV) dichloride in the presence of a base. The compounds have been investigated by elemental analysis and IR, 1H NMR, and 119Sn NMR spectroscopies. Spectroscopic studies show that the hydrazone is a tridentate dianionic ligand, coordinating via the imine nitrogen and phenolic and enolic oxygens. The structures of H2Lb and 3 have also been confirmed by X-ray crystallography. The results show that the structure of 3 is a distorted square pyramid with imine nitrogen in apical position. The in vitro antibacterial activities of ligands and complexes have been evaluated against gram-positive (Bacillus cereus and Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. H2La and H2Lb show no activity but the diphenyltin(IV) complexes exhibit good activities towards two bacterial strains in comparison with standard bacterial drugs.

Transmetallation reactions of [Sn(R)2(Ph2PC6H4-2-S)2] with metal complexes of the Group 10: Stereoselective synthesis of cis-[M(Ph2PC6H4-2-S)2] (M=Ni, Pd, Pt)

Abstract The complexes cis -[M(Ph 2 PC 6 H 4 -2-S) 2 ] M=Ni, Pd, Pt were stereoselectively synthesized by transmetallation reactions of [M(Cl) 2 (NCC 6 H 5 ) 2 ] M=Pd, Pt or NiCl 2 ·6H 2 O with [Sn(R) 2 (Ph 2 PC 6 H 4 -2-S) 2 ] R=Ph, n Bu or t Bu. The conformation of the Pd and Pt derivatives being unequivocally confirmed by single crystal X-ray diffraction studies showing both metal centers to be into a slightly distorted square planar environment, the main distortion being due to the steric hindrance caused by the aromatic rings in the phosphine moiety.

Allyl–palladium complexes with fluorinated benzene thiolate ligands. Examination of the electronic effects in the Pd-catalyzed allylic alkylation reaction with the catalytic system [(η3-C3H5)Pd(μ-SRf)]2/PR3

Abstract The bimetallic complexes [(η 3 -C 3 H 5 )Pd(μ-SR f )] 2 [R f =C 6 F 5 , ( 1 ); C 6 F 4 H-4, ( 2 ); C 6 H 4 F-2, ( 3 ); C 6 H 4 F-3, ( 4 ) and C 6 H 4 F-4, ( 5 )] in the presence of para -substituted phosphines P(C 6 H 4 X-4) 3 [X=OCH 3 , CH 3 , H, F, Cl, and CF 3 ] are efficient catalytic systems in the allylic alkylation couplings of ( E )-3-acetoxy-1,3-diphenyl-1-propene and dimethyl malonate. Results concerning the electronic effects of both sulfur and phosphorus substituents in this reaction are discussed.